+ Gradient &operator+=(const Gradient &rhs);
+ Gradient &operator-=(const Gradient &rhs);
+ Gradient &operator*=(const float &rhs);
+ Gradient &operator/=(const float &rhs);
+
+ Gradient operator+(const Gradient &rhs)const { return Gradient(*this)+=rhs; }
+ Gradient operator-(const Gradient &rhs)const { return Gradient(*this)-=rhs; }
+ Gradient operator*(const float &rhs)const { return Gradient(*this)*=rhs; }
+ Gradient operator/(const float &rhs)const { return Gradient(*this)/=rhs; }
+